Every device that is connected to the Internet has a unique identifier known as IP (Internet Protocol) address. This includes personal computers, web servers, smartphones, switches, etc. The pool of addresses, that was introduced initially, is already distributed, hence the so-called IPv4 IP addresses are steadily getting replaced with IPv6 addresses. Every domain name which opens a site has an IP record, which is the address of the server where it is hosted. With the IPv4 system, the record is called A and it is comprised of 4 groups of numbers from 1 to 255 separated with a dot, while in the IPv6 system it's called AAAA and it is made up of eight sets of hexadecimal numbers i.e. this sort of records use numbers from 0 to 9 and letters from A to F. A good example of an AAAA record is 2010:0c48:43d3:2142:1012:8c3a:2475:2435 and this format supports a substantially greater amount of IPs than the IPv4 format.